There are only two remaining monk seal species which are the mediterranean monk seal and the hawaiian monk seal. Female monk seals are slightly larger than males, reaching from 7.5 feet in length and 450 lbs.Males reach 7 feet in length and weigh up to 375 lbs. Adlut monk seals have grey colored backs, and a lighter color on their underside. Red and green coloration may be present due to attached algae. The backs of these animals may darken with time (especially in males). They have a 25-30 years life expectancy. The maturity of females beings at age 5-6, but the maturity of males is unknown.